1. Field of Invention
The invention relates to a fan and a switch control device thereof, and in particular, to a fan capable of controlling the provision of a power, and a switch control device thereof.
2. Related Art
Requirements on the functions of electronic apparatus are getting higher and higher, and the number of various accessory apparatuses is getting higher and higher. When the electronic apparatus of a system is in a standby state, it stores a small power for the electronic apparatus in order to keep the rapid starting state. Although the system has stopped operating when the electronic apparatus is in the standby state, peripheral elements or circuits of the electronic apparatus, e.g., a fan, receive and consume the power since the small power is still stored in the electronic apparatus. Thus, the quality and the power consumption of the electronic apparatus and the system, such as a notebook computer equipped with a battery, are influenced.
Illustrations will be made by taking the fan of the notebook computer as an example. Referring to FIG. 1, a conventional fan 1 has a drive control device 11, a motor 12 and a plurality of peripheral elements 13 for the fan, and receives a pulse width modulation (PWM) signal SPWM inputted from the outside and a power Vd. The drive control device 11 has a predetermined value D1 for stopping the fan. When the notebook computer in on standby, the pulse width modulation signal SPWM is lower than the predetermined value D1, and the drive control device 11 stops the motor 12.
Although the motor 12 has stopped operating, the peripheral elements 13 still keep consuming the working power because the small power is still fed into the fan 1. If the notebook computer is powered by a battery, the peripheral elements 13 use up the power of the battery so that the notebook computer cannot be started or used immediately.
The above-mentioned condition occurs not only in the notebook computer but also in various electronic hand-held apparatuses or products powered by batteries. When the apparatus is on standby or shuts down, the peripheral elements pertaining to the fan still continuously consume the working power. Thus, the power in the battery of the electronic apparatus or product is used up, and the electronic apparatus or product cannot be started or used immediately. It is more serious to the electronic apparatus or product which is aimed on the power consumption because the use is lowered and the power is wasted.
Thus, it is an important subject of the invention to provide a fan capable of controlling the provision of a power and a switch control device thereof, wherein the power supplied to the fan is stopped when the fan stops so that the peripheral elements of the fan cannot continuously consume the working power.